Active dry yeast containing a sucrose diester



United States Patent 3,410,693 ACTIVE DRY YEAST CONTAINING A SUCROSEDIESTER Seymour Pomper, Stamford, Conn., and Emanuel Akerman, Bronx,N.Y., assignors to Standard Brands Incorporated, New York, N.Y., acorporation of Delaware No Drawing. Filed Oct. 20, 1965, Ser. No.499,023 Claims. (Cl. 99-96) ABSTRACT OF THE DISCLOSURE An active dryyeast comprising yeast having a moisture content below about 7.5 percentby weight and a small amount of sucrose diester derived from a saturatedfatty acid having a carbon chain length greater than 12. The sucrosediester imparts to the yeast superior leavening activity. Examples ofsuitable sucrose diesters are sucrose distearate and sucrosedipalmitate.

This invention relates to a novel active dry yeast product and a processfor preparing the same.

Commercial active dry yeast, sold today, is a yeast product which hasbeen dehydrated under controlled conditions to a moisture content ofabout 8 percent by weight. The keeping qualities and cool watertolerance of yeast are directly dependent upon its moisture content. Athigh moisture levels, yeast will have poor keeping qualities while atlow moisture levels it will have good keeping qualities. However, in thecase of the cool water tolerance of yeast, just the opposite is true;that is, at high moisture levels cool water tolerance will be g while atlow moisture levels it will be poor. Cool water tolerance is a measureof a yeasts leavening activity after it has been rehydrated in coolwater; for instance, in water at 70 F. Also, during the dryingprocedure, an appreciable part of the yeasts leavening activity isdestroyed. Thus, the 8 percent moisture level has been selected so thatthe active dry yeast has relatively good keeping qualities, itsleavening activity has not been damaged to too great an extent and ithas fair cool water tolerance.

It is the principal object of the present invention to provide a lowmoisture active dry yeast with improved initial leavening activity. Itis a further object of the present invention to provide an active dryyeast which may be rehydrated in cool water without substantialreduction of its leavening ability. A still further object of the present invention is to provide a dry yeast with a high degree of storagestability.

We have found that the above objects may be accomplished byincorporating into yeast, prior to drying the yeast, a small amount of asucrose diester derived from a saturated fatty acid having a carbonchain length greater than 12.

Examples of sucrose diesters which we found to be preferable are sucrosedistearate and sucrose dipalmitate manufactured by Colonial SugarsCompany and sold under the code designations SES-Z, P-1 and SEP-2, P1respectively. In the Bulletin SE-l, 2 III (3/24/64) entitled Colonial SESurfactants distributed by Colonial Sugars Company it is mentioned thatthe largest proportion of the fatty acid groups may well be on the twoprimary hydroxyls at the extreme ends of the sucrose molecule.

The diesters may be introduced into the yeast at any point prior todrying the yeast provided they are substantially uniformly distributedin the final dried yeast. It is convenient to form a fine suspension oremulsion of the diester in a suitable solvent, heat the suspension or3,410,693 Patented Nov. 12, 1968 emulsion with stirring until thediester is substantially dis solved and then mix the solution directlywith cream or compressed yeast.

The amount of diester, based on the weight of the final active dry yeastproduct, may vary over a relatively wide range. Very small amounts havegiven beneficial results, for example 0.5%. However, the preferredamount of the diester varies between about 1 and about 3 percent byweight. Larger amounts may be added but they d not appear to confer anyadditional benefit.

A further embodiment of the invention is the provision of ananti-oxidant in the active dry yeast product of the present invention.Examples of suitable antioxidants are butylated hydroxyanisole andbutylated. hydroxytoluene. These antioxidants stabilize the dry yeastproduct so that it may be stored under atmospheric conditions withoutincurring substantial loss of its leavening activity. Very small amountsof the antioxidant are sufficient, for instance, about 0.025 to about0.5 percent based on the weight of the yeast solids. Larger amounts maybe used but they do not appear to confer any additional benefit. Thegreatest benefit seems to be obtained with amounts between about 0.1 andabout 0.2 percent.

The antioxidant may be incorporated in the moist yeast at any stageprior to drying the yeast. It is convenient to add the antioxidant insolution in an edible carrier. Exemplary of edible carriers we prefer touse are vegetable oils which are liquid at room temperatures, forinstance, peanut oil, soybean oil, corn oil, cottonseed oil, sunfloweroil and safflower oil. However, edible carriers which are solid at roomtemperature may be used by simply heating the carrier above its meltingpoint before admixing with the antioxidant and maintaining thistemperature while the solution is being incorporated into the yeast.Synthetic edible carriers may also be used, for instance, propyleneglycol. The moisture content of the active dry yeast of the presentinvention should be below about 7.5 percent by weight and preferablybetween about 4 and about 7 percent by weight.

In order to more clearly describe the nature of the present invention,specific examples will hereinafter be described. It should beunderstood, however, that this is done solely by way of example and isintended neither to delineate the scope of the invention nor limit theambit of the appended claims. In the example and throughout thespecifications, percentages are intended to refer to percent by weightunless otherwise specified.

EXAMPLE I This example illustrates the preparation of active dry yeastproducts of the present invention and their leavening superiority overcontrol samples both initially and after storage in an inert atmosphere.

18.4 grams of sucrose dipalmitate were suspended in 368 ml. of a 1% NaOHsolution and the suspension heated to 170 F. This suspension was cooledto 140 F. and slowly incorporated with mixing into 4 kg. of cream yeastcontaining 22.9 percent solids. The treated yeast was stirred forone-half hour and concentrated by filtration and pressing to 35 percentyeast solids. The yeast was then extruded into spaghetti form and driedin a temperature range from to 120 F. and at a relative humidity of fromabout 70 to about 10 percent. The drying time was about 7 hours.

The dried yeast was tested for its initial leavening activity in a sweetdough formula and also tested for leavening activity after storage forseven days at F. in nitrogen.

Prior to the preparation of the sweet dough, the dry yeast wasrehydrated in warm water (100 F.). Leavening activity is defined asfollows:

Fermentation time EXAMPLE III This example illustrates the eff ct ofsucrose esters on the leavening activity of yeast which has beenrehydrated in warm and cool water. The sucrose esters selected for Thetime required for a given weight of sweet dough, 5

maintained at 86 F., to rise to a predetermined volume. testmg W thosewlthm and without the scope of the present lnventlon. Proof timeDiesters The time required for the dough to reach this Volume 7.8 gramsof sucrose distearate were suspended in 156 at the same temperatureafter being Punched dOWhml. of a 1% NaOH solution and the suspensionheated to The m procedure as above was d for addlng 170 F. in minutes,cooled to 160 F. and slowly insucrose dlstearate and the effect of thisdlester on the .corporated 2 kg of yeast containing 195 percent hetlve yYeast Was tested In the Same e solids and with thorough mixing. Thetreated yeast was The results of these tests are Shown 111 Tableconcentrated by vacuum filtration and pressing to 34.7

TABLE I 15 percent solids. A small amount of water was added to thepressed cake to adjust the solids content to 32 percent. L At t InitialLeavening iihi sifimejigl- The yeast was then extruded into spaghettiform and dried Treatment Peicent Actlvlty fi i in a ten1perature rangefrom 95 to 120 F. and at a moisture relatlve humidity of from about 70to about 10 percent.

Egg The drying time was about 6 hours. Time Time 4.3 grams of sucrosedlpalmltate were suspended 1n 33 Cont 01 m 88 63 157 131 ml. of peanut011 and the suspens1on heated to 170 F. in o 4.7 153 106 152 141 5minutes, added to 110 ml. of water at 120 F. and f fi f ?fhf 4'9 89 6393 73 blended for 10 minutes in a Waring Blendor. This prep 2% SucroseDistearatlon was cooled to 95 F. and added to 1 kg. of cream 6 89 68 10480 yeast having a solids content of 21.5 percent. The treated yeast wasconcentrated by vacuum filtration and pressing EXAMPLE H to 33 percentsolids. This sample was extruded and dried This example illustrates thepreparation of active dry in the same manner described above. yeastproducts of the present invention and compares Monoesters theirleavening activity after being rehydrated both in d d water at 100 F.and 70 F. with the leavening activity of sucrosehmonosteatate g g i g gof control samples. Also this example illustrates the high i i watfirl ag g i i gate to t d degree of storage stability of the active dry yeastproducts f C00 6 to i S OW y lncolporafa Into of the present invention35 1 kg. or cream yeast containing 20.0 percent sollds and 4 grams ofsucrose distearate were suspended in 80 ml. g 9 g i g mlxed Thetreatedbyeast was concentrated and of a 1% sodium hydroxide solution andthe suspension e saline manner as a t d was then heated to about 170 F.To this suspension was z fi h i i f if added 1.6 grams of a BHA-peanutoil solution, also at t i xif an suspenstlgn i 170 F., containing 0.2gram BHA. This suspension was 40 0 d l 1 e l p i k en fcooe 0 t dilutedwith ml. of hot tap water and blended in a 2 g i e 2 f 0 f fi WaringBlendor for a few minutes, after which it was treatficgl ea'st i g" d gi e cooled to about 130 F., added to 1 kg. of cream yeast Her as gbovewas c0 en r e an ne 6 same mancontaining 20 percent yeast solids andmixed for 15 4 Grams f Sucrose monolaurate w S d 45 minutes. The treatedyeast was concentrated by vacuum 45 1 d h h ere uspin e filtration and dth t ded d d d th m 0 water an t e suspens1on eated to 160 F., cooledpressing an en exru an rie 1n e t F o and added to 1 kg. of cream yeastcontaining 20 same manner as Example I. Another sample was prepared inexactl the same manner exce t BI-IT was substituted percent yeast SohdsWlth thorough mlxmg' The treated y P yeast was concentrated and dried inthe same manner as for BHA. above Pgrtlons of the products wererehydrated 1n water at 00 Sucrose monopalmitate was used in preparing ayeast 100 and and then checked for leavenmg sample This sample washandled in the same manner as activity in a sweet dough formula. Otherportions of the the 0 preceding sample. products were stored for 7 daysat 115 F. 1n an oxygen containing atmosphere and then checked forleavening s turated sucrose ester activity in a sweet dough formula. Theresults of the 55 4grams of sucrose dioleate were suspended in ml. oftests are given in Table II. a 1 percent NaOH solution and thesuspension heated to TABLE II Leavening Activity After Storage forRehydrated at Rehydrated at 7 Days at 115 F.

100 F. 70 F. in an Oxygen Treatment Percent Containing Atmos- Moisturephere 1 Fermen- Proof Fermen- Proof Fermen- Proof tation Time tationTime tation Time Time Time Time Control. 7. 7 7s 64 97 79 169 146 Do-4.8 126 100 (a) 173 142 2% sucrose distearate +01% BH 4.7 32 66 68 10987 2% sucrose distearate +01% BHT 4.6 83 64 89 69 109 93 1 These sampleswere rehydrated at F.

1 Over 300.

s Very slow.

190 F. with stirring. To this suspension was added ml. of hot Water andthe suspension blended for a few minutes in a Waring Blendor and cooledto about 130 F. This suspension was added to 1 kg. of cream yeastcontaining 20 percent yeast solids and then mixed for 15 minutes. Thetreated yeast was concentrated and dried in the same manner as above.

Portions of the yeast samples were rehydrated in water at 100 F. and F.and then checked for leavenin'g activity in a sweet dough formula. Theresults of the tests are given in the following Table III. These resultsshow that sucrose esters which are not within the scope of the presentinvention detrimentally affects the leavening activity of yeastrehydrated in water at 70 F.

TABLE III Leavening Activity of the Dried Yeast Rehydrated at Rehydratedat Treatment Percent 100 I 70 F.

Moisture Fermen- Proof Fermen- Proof tation Time tation Time Time TimeControl 7. 7 94 73 146 117 2% Sucrose Distearate 7. 0 86 69 89 72Control 7.8 85 67 114 86 2% Sucrose D palmitute 6. 9 80 65 100 Control8.1 84 66 108 2% Sucrose Monostearate 6. 1 91 73 164 124 Control H 8. 485 64 107 83 2% Sucrose Monomyristate 7. 0 104 89 225 Control 8. 1 93 73123 97 2% Sucrose Monourate G. 6 134 329 0) Control 8. 1 84 66 108 80 2%Sucrose Monopalrnitate 7.1 97 76 130 Control 7. 7 78 64 99 79 2% SucroseDioleate 6. 7 90 69 173 132 Very slow.

What is claimed is:

1. An active dry yeast comprising yeast having a moisture content belowabout 7.5% by weight and a small but effective amount of a sucrosediester derived from a saturated fatty acid having a carbon chain lengthgreater than 12, which ester imparts to said yeast superior leaveningactivity.

2. An active dry yeast as defined in claim 1, wherein the moisturecontent is from about 4 to about 7 percent by weight.

3. An active dry yeast as defined in claim 2, wherein the sucrosediester is selected from the group consisting of sucrose distearate andsucrose dipalmitate.

4. An active dry yeast as defined in claim 3, wherein the amount ofsucrose diester is between about 1 and 3 percent by weight based on theweight of the yeast solids.

5. An active dry yeast as defined in claim 1, containing a small amountof an antioxidant effective to impart substantial storage stability inair to said yeast.

6. An active dry yeast as defined in claim '5, Wherein the antioxidantis butylated hydroxyanisole or butylated hydroxytoluene.

7. An active dry yeast as defined in claim 5, wherein the sucrosediester imparts to the yeast the characteristic that it can berehydrated in water at a temperature of about 70 F. without substantialreduction of its leavenin'g activity occurring.

8. An active dry yeast as defined in claim 6, wherein the amount ofantioxidant is between about 0.025 to about 0.5 percent by weight basedon the weight of the yeast solids.

9. An active dry yeast as defined in claim 4, wherein the sucrosediester is provided in the active dry yeast by forming an aqueousalkaline suspension of the diester, incorporating the suspension into anaqueous suspension of yeast cells and drying the yeast to a moisturecontent of below about 7.5 percent by weight.

10. An active dry yeast as defined in claim 3, containing between about0.025 and about 0.5 percent by weight based on the weight of the yeastsolids of an antioxidant selected from the group consisting of butylatedhydroxyanisole and butylated hydroxytoluene.

References Cited UNITED STATES PATENTS 2,894,842 7/ 1959 Mitchell 99-963,041,249 6/1962 Chen et a1. -74

-A. LOUIS MONACELL, Primary Examiner.

D. M. NAFF, Assistant Examiner.

